Engaging yne-allenones in tunable catalytic silane-mediated conjugate transfer reductions.

New tunable catalytic [2+2] cycloaddition/silane-mediated conjugate transfer reductions of yne-allenones have been developed, by which substituent-diverse cyclobutarenes with generally good yields were selectively synthesized by adjusting Fe-H and Cu-H catalytic systems. Use of the Fe-H system triggers 1,6-conjugate reduction to dihydrocyclobuta[a]naphthalen-4-ols whereas the Cu-H complex enables 1,4-conjugate reduction to cyclobuta[a]naphthalen-4(2H)-ones.

Catalytic Three-Component Synthesis of Functionalized Naphtho[2,1-b]oxecines via a Double Bond Cleavage-Rearrangement Cascade.

A new double annulation cascade involving a [2 + 2] cycloaddition-retroelectrocyclization (CA-RE) process was first reported, leading to the generation of unprecedented dibenzoannulated naphtho[2,1-b]oxecines with good to excellent yields and high stereoselectivity through catalytic scission/recombination of C-C double bonds under the mild conditions. An Y(OTf)3-catalyzed three-component reaction of α-alkynyl naphthalen-2-ols with ß,γ-unsaturated α-ketoesters enabled direct ring expansion of the naphthalene ring and carbon-carbon double bond cleavage/rearrangement of α-ketoesters to give macrocyclic architectures.